Portion of a wiper



FIG. 1 is a front right perspective view of a portion of a wiper showing our new design;

FIG. 2 is a front view thereof;

FIG. 3 is a rear view thereof;

FIG. 4 is a left side view thereof;

FIG. 5 is a right side view thereof;

FIG. 6 is a top view thereof; and,

FIG. 7 is a bottom view thereof.

The dash-dot-dash broken lines immediately adjacent to the shaded areas represent unclaimed boundaries of the claimed design. The dotted broken lines are for illustrative purposes only and form no part of the claimed design. 

The ornamental design a portion of a wiper, as shown and described. 